Two-cycle engine axial scavenging of cylinders



July 25, 1950 N, MACY ErAL 2,516,228

TWO-CYCLE ENGINE AXIAL SCAVENGING 0F CYLINDERS Filed Oct. 31, 1945 INVENTORS. /Vn mmv/a der Gao/verf'. scf/afn. zu BY fra Mfrs.

Patented .uly 2 5,` 1950 TWO-CYCLE ENGINE AXIAL SCAVENGING F CYLINDERS Nathaniel Macy and George F. Schafer,

Greencastle, Ind.

Application October 3l, 1945, Serial No. 625,756

9 Claims. (Cl. 123-65) This invention relates to a V-type two cycle internal combustion engine.

The chief object of this invention is to improve the operating characteristics and increase the power output of such an engine.

The chief feature of this invention resides in an air compressor common to both v-arranged cylinders and cylindrically operable in dual relation to any power pistonv operation, and in positively supplying fuel at a predetermined portion of the piston cycle to the associated cylinder.

Another feature of the invention resides in the simultaneous air and fuel control whereby throttling is accomplished without substantial variation of fuel-air ratio.

Other objects and features the ini/.ention will be set forth more fully hereinafter.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims:

In the drawings Fig. l is a semi-diagrammatic transverse sectional view of a V-arranged multiple cylinder engine with an interposed singular air compressor, the crank case and crank shaft bearings being omitted for clearness.

Fig. 2`is a longitudinal sectional view of the fuel supply nozzle and an elevational view of the power and control associated parts.

Fig. 3 is an enlarged central sectional view of a check valve in the fuel supply line that is suction operable by injection plunger retraction and is plunger pressure seatable.

In Fig. 1 of the drawings I 0 indicates a power cylinder, water-jacketed for cooling as at II and displaced approximately 90. Note also that the followers 28 are displaced about 90 so that single cam 21 can successively'actuate each. Each power cylinder I 0 near the end of the piston stroke, see left hand cylinder in Fig. l. includes an annular channel 33 having free communication with the cylinder by ports 34. Conduits 35 connect the channels 33'to the air cylinderl I3. Obviously, when power piston I2 is compressing or nal scavenging the ports 34 are cut off by said piston from cylinder II communication.

vThe air supply includes valve seat 36 in the head end of cylinder I3 controlled by valve 31 light spring constrained to closed position. This is a check valve and opens on suction in cylinder I3 and closes upon pressure therein.

Enveloping the head end ofthe air cylinder I3 is hood or air intake manifold 38 which has an intake opening 39a, but said intake is controlled by buttery valve 39 therein and on shaft 40 that, externally of the manifold, mounts pinion 4I meshing with rack 42.

having therein powery piston I2. The two cylinders illustrated are shown in V-arrangement and therebetween is an air compressorvcylinder I3 in which is mounted air piston I4.

Each power piston has water-jacketed head I5 provided with exhaust conduit I9 controlled by poppet valve I1 normally constrained by its spring I8 to seat I9. Stem 20 is rocker arm actuated, 2| indicating the rocker, and 22 generally indicating the tappet and tappet guide, etc. Rocker arm 2I is supported at 23 upon the head and all the aforesaid may be 'enclosed as at 24. Plug 25 is also head mounted.

Herein a cam shaft 26 includes cam 21 that successively engages followers 23` of the tappet structure. 29 indicates the crank shaft having eccentric portions 30 to which are connected' rods 3l, in turn connected by wrist, pins 32 to the power pistons I2. The two portions 30 have the relative positions as shown, that is, same are Air compressor piston I4 includes rod 43 guided as at 44 and said stem at its outer, lower free end mounts follower roll 45. Associated with the stem is spring 46 normally constraining the piston to suction action and the` follower to engagement with cam 41 carried by the crank shaft A29. This cam has a gradual elevation portion 48 and a quick drop portion 49.

The cam illustrated is of dual character so that for each revolution of the crank shaft piston I4 is twice reciprocated. From the foregoing it is obvious that piston I4 is quickly lowered by spring 46 when cam freed, as it were, to suck in air past check valve 31, which opens upon suction, and from the air manifold or header controlled by air valve 39.

When the suction stroke is completed the piston I4 is cam actuated to compress the air trapped in cylinder I3, and this compressed air is supplied by conduits 35 to annular channels 33 about the power cylinders II).

If the power piston I2 is suiiiciently lowered due to a previous combustion stroke, the ports 34 will be uncovered and the compressed air will discharge to cylinder I0. Exhaust valve I1 having opened, it will be clear that the exhaust gases are blown out passage I6 by the inrushing new air charge.

When suiilcient scavenging occurs and before fuel intake occurs exhaust valve I1 is closed and air under. pressure is supplied to the cylinder I0 for combustion purposes until the rising pis- 2,5 lanas ton i2 cuts oi! ports Il. The air trapped in the power cylinder is then compressed to the volume shown in the right end 1of Fig. l, whereupon at dead center, or slightly before or after as desired, and determined by a timer mechanism (not shown) operable from the cam shaft 28 supplies a spark at plug 2l. Upon ignition of the combustible mixture.` the power stroke of the piston l2 is effected.

Reference will now be had more particularly to Fig. 2 wherein the pressure fuel supply is illustrated. The cam shaft 2l has cam 60 thereon that engages follower roll il carried by arm B2 pivoted at Il and engaging piston rod 65 slidable in bore Il of nozzle l1.

This nozzle has a fuel supply i8 leading to a check valve l! in turn feeding to conduit 'l0 opening into tip 1i which has outlet 'i2 registering with port 13 in cylinder wall ill. For clearness only. ports 13 are'illustrated in Fig. l.

The nozzle l1 has threaded chamber 64 coaxial with bore .f Threaded therein is thlmble gine operable, means operable in timed relation to piston operation and communicating with said ports, and fuel supplying means communicating 1 with the cylinder and also operable in timed relation to piston operation, the timing being such that compressed air initially scavenges the cylinder prior to fuel supply thereto, and means simultaneously regulating fuel and air intake for engine control at substantially constant predetermined fuel to air ratio. t

3. In a two-cycle engine having a power cylinder and piston, the cylinder having air intake ports near the end of the stroke and exhaust 1l with inner closed end 16 that is apertured to slidably support plunger stem 65. A coil spring 11 bears against end 10 and is retained by retainer 1l adjustably mounted on stem 65. 4

When follower ll is not engaged with cam il the spring 11 tilts arm l2 counter-clockwise on pivot 83 and retracts the plunger 65 in bore 6I. Upon this retractionA fuel is drawn through the check valve Il, see Fig. d, to the nozzle tip chamber 1I and that part of the bore 66 vacated by the plunger.

When follower Il is engaged by cam 60, lever I2 is tilted clockwise and plunger 65, against.

spring 11, is forced toward the tip. In so doing check valve il is automatically seated and the fuel, now under pressure, is discharged at port 18 to the power-cylinder il.

Thimble 1I on its nozzle exposed end mounts a pinion Il that `meshes with rack 42 aforesaid and the thlmble by rack reciprocation through pinion Il is caused to further nest in chamber Il of the nozzle or project therefrom, thus determining the amount of fuel pumped.

Also, the fuel and air issimultaneously varied, that is, increased `or decreased so that fuel to air ratio is substantially constant. Rack 42 may be foot or hand throttle actuated and, obviously, for self-propelled vehicles would be set for low idle at minimum supply. Starting and stopping may then'be effected by ignition circuit control -to the plugs through a master switch, not shown.

While the invention has been illustrated and described in great detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character. v

The several modifications described herein, as well as others which will readily suggest themselves to persons skilled in this art, all are considered to be within the broad scope of the invention, reference being had to the appended claims.

The invention claimed is:

l. In a two cycle engine having a relatively stationary power cylinder and a piston therein,

' the cylinder having Aair intake ports near the end of the stroke, and poppet type exhaust valve means operablein timed relation with piston travel, the combination of air compressing, auxiliary means operable'in timed relation to piston operation and vcommunicating with said' ports, and fuel vsupplying means communicating with the cylinder nearthe intake end thereof and means operable in timed relation with piston travel. the combination of air compressing, engine operable, means operable in timed relation to piston operation and communicating with said ports, and fuel supplying means communicating with the cylinder and also operable in timed re.- lation to piston operation, the timing being such that compressed air initially scavenges the cylinder prior to fuel supply thereto, the fuel supplying means including a nozzle, a plunger reciprocable therein normally constrained to movement in one direction, engine operable means for timed movement of the plunger in the opposite direction and in opposition to the constraint, said nozzle having a tip discharge to the engine cylinder and a check valve controlled fuel supply to the nozzle.

4. In a two-cycle engine having a power cylinder and piston, the cylinder having air intake ports near the end of the stroke and exhaust means operable in timed relation with piston travel, the combination of air compressing, engine operable, means operable in timed relation to piston operation and communicating with said ports, and fuel supplying means communicating with the cylinder and also operable in timed relation to piston operation. the timing being such that compressed air initially scavenges the cylinder prior to fuel supply thereto, the fuel supplying means including Va nozzle, a plunger reciprocable therein normally constrained to movenint in one direction, engine operable means for t direction and in opposition to the constraint, said nozzle having a tip discharge to the engine cylinder, a check valve controlled fuel supply to the nozzle, and means interposed between the nozzle and plunger for regulating the stroke thereof for fuel variation.

5. In a two-cycle engine having a power cylinder and piston, the cylinder having air intake ports near the end of the stroke and exhaust means operable in timed relation .with piston travel, the combination of air compressing, engine operable, means operable in timed relation to piston operation and. communicating with said ports, and fuel supplying means communicating with the cylinder and also operable in timed relation to piston operation, the timing being such that compressed air initially scavenges the cylinder prior to fuel supply thereto, the air supplying means including a cylinder, a valve controlled intake thereto, said air cylinder freely commued movement of the plunger in the opposite nicating with the power cylinder ports, and piston means in the air cylinder for charging thereof and compressing the air trapped in the air cylinder.

6. In a two-cycle engine having a power cylinder and piston, the cylinder having air intake ports near theend of the stroke and exhaust means operable in timed relation with piston travel, the combination of air compressing, engine operable, means operable in timed relation to piston operation and communicating with said ports, and fuel supplying means communicating with the cylinder and also operable in timed relation to piston operation, the timing being such that compressed air initially scavenges the cylinder prior to fuel supply thereto, the air supplying means including a cylinder, a valve controlled intake thereto, said air cylinder freely communicating with the power cylinder ports, and piston means in the air cylinder for charging thereof and compressing the air trapped in the air cylinder, the air pistonv being normally constrained to movement in one direction and engine power movable in the opposite direction.

7. In a two-cycle engine having a power cylinder and piston, the cylinder having air intake ports near the end of the stroke and exhaust means operable in timed relation with piston travel, the combination of air compressing, engine operable, means operable in timed relation to piston operation and communicating with said ports, and fuel supplying means communicating with the cylinder and also operable in timed relation to piston operation, the timing being such that compressed air initially scavenges the cylinder prior to fuel supply thereto, the air sup.- plying means including a. cylinder, a valve controlled intake thereto, said air cylinder freely communicating with the power cylinder ports, and piston means in the air cylinder for charging thereof and compressing the air trapped in the air cylinder,an air intake manifold for said air cylinder, the intake being included therebetween, the manifold having an intake opening to atmosphere, and valve means for controlling the amount of second mentioned intake opening.

8. In a two-cycle engine having a power cylinder and piston, the cylinder having air intake ports near the end of the stroke and exhaust means operable in timed relation with piston travel, the combination of air compressing, engine operable, means operable in timed relation to piston operation and communicating with said ports, and fuel supplying means communicating with the cylinder and also operable in timed relation to piston operation, the timing being such that compressed air initially scavenges the cylinder prior to fuel supply thereto, the air supplying means including a cylinder, a valve controlled intake thereto, said air cylinder freelycommunicating with the power cylinder ports, and piston means in the air cylinder for charging thereof and compressing the air trapped in the air cylinder, an air intake manifold for said air cylinder, the intake being included therebetween, the manifold having an intake opening to atmosphere, and valve means for controlling the amount of second mentioned intake opening, said valve means being of butterfly type.

9. In a two-cycle engine having a power cylinder and piston, the cylinder having air intake ports near the end of the stroke and exhaust means operable in timed relation with piston travel, the combination of air compressing, engine operable, means operable in timed relation to piston operation and communicating with said ports, and fuel supplying means communicating with the cylinder and also operable in timed relation to piston operation, the timing being such that compressed air initially scavenges the cylinder prior to fuel supply thereto, the air supplying means including a cylinder, a valve controlled intake thereto, said air cylinder freely communicating with the power cylinder ports, and piston means in the air cylinder for charging thereof and compressing the air trapped in the air cylinder, an air intake manifold for said air cylinder, the intake being included therebetween, the manifold having an intake opening to atmosphere, and valve means for controlling the amount of second mentioned intake opening, said valve means being of butterfly type, the air piston being normally constrained to movement in one direction and engine power movable in the opposite direction.

GEORGE F. SCHAFER. NATHANIEL MACY.

REFERENCES CITED The Afollowing references are of record in the ille of this patent:

UNITED STATES PATENTS France of 1920 

